The good/bad luck of King Felix in 2015

So far in 2015, Felix Hernandez has pitched... like a king. With the exception of his most recent start, Felix has been pretty lights out for the entire season. He's clearly one of the best pitchers in MLB (duh) and his performance in April and May this year represented one of the best two-month stretches of his career. Even with his struggles against the Yankees on Monday, he's at/near the top of most pitcher leaderboards.

As I mentioned last week, Felix continues to hone his craft and find ways to improve himself as a pitcher. He's amazing and it seems as though he's well on his way to another stellar season. However, in addition to being legitimately great in 2015, Felix also appears to be experiencing quite a lot of luck (both good and bad) this year. Let's look at some numbers!

The good luck

A few pitchers have been able to put up well-below-average BABIP numbers for the length of their careers (recent examples include Matt Cain and Johan Santana), but Felix has actually been right around league-average. This season, however, despite what would be a career-high GB%, Felix's BABIP has been 44 points lower than his career average. Because the Mariners overall infield defense has been largely mediocre in 2015, this low BABIP probably suggests a fair amount of luck.

Additionally, Felix's strand rate this season been super low. Historically, Hernandez has been good at stranding runners (because he's a beast who can dominate all over batters when he finds himself in a jam), but over a full season his LOB% has never been higher than 77%. This could also be indicative of a pretty lucky season so far.

These metrics suggest that there's a good chance that Felix has been overperforming a little bit this season. As the year progresses, Felix's BABIP will probably rise and his LOB% will probably fall. Steamer predicts that Felix's BABIP and LOB% will be 0.302 and 75.4%, respectively, over the remainder of the season. Unsurprisingly, these numbers are near his career averages; however, even with a bit less luck, King Felix should continue to put up marvelous numbers in 2015.

The bad luck

On the other side of the coin, we have Felix's HR/FB%. So far this season, one out of every five fly balls that Felix has allowed has landed on the other side of the outfield fence. That's so many! Fortunately for Felix, seven of those eight home runs have been solo shots; nonetheless, HALF of the 22 runs that he's allowed in 2015 have come as a result of the long ball. It should also be noted that Felix's FB% this season has been very low, so his overall HR/9 numbers are near league-average, but still... this is very uncharacteristic.

Despite possessing a high HR/FB rate early in his career, Felix has put up ~league-average or better numbers each of the last seven seasons. It's still fairly early in 2015, but this year has been a complete aberration so far. Even if Felix gives up home runs on fly balls at a career average clip for the remainder of the season, he'll still likely put up his highest HR/FB% since 2007 (by a wide margin).

Will all these home runs continue?

No. A good deal of regression will almost certainly occur; the likelihood that Felix continues to give up dingers at such a high rate is exceedingly unlikely. For reference, below is a table showing the highest HR/FB percentages each year for the last 10 seasons.

We can see that none of these pitchers had a HR/FB% of 20+%. In fact, since 2005, only six of the 844 qualified starting pitcher seasons had a HR/FB% above 17%. Felix's current HR/FB% is almost four standard deviations away from the average value over the last 10 years! That is a lot. He's definitely in line to start recording more fly outs as the season continues and his HR/FB rate should steadily become less insane.

But why are so many fly balls being hit for home runs?

Finally, why is this even happening? Why has Felix been snakebitten on one fifth of the fly balls that he's allowed? Is it simply bad luck? (Probably.) Or maybe something else going on? (Probably not.)

Below is a heat map showing the location of the pitches for the home runs surrendered by your King in 2015.

It's pretty clear that Felix isn't getting beat on any of his pitches. (Six of these offerings were sinkers, one was a slider, and one was a four-seam fastball; nobody this season has punished Felix's changeup or curve.) These all look like they could have been mistakes, with each pitch catching a large portion of the plate. So maybe Felix has simply been missing out over the plate more often this year? Enabling batters who do hit the ball in the air to smash it a long way? To see whether or not this is happening, we can look and see how many pitches Felix has been groovin' this year.

A grooved pitch is simply an offering that is located very near to the center of the plate. These could be hanging breaking balls, but they could also be intentional "get me over" strikes. In either case, this graph clearly shows that Felix hasn't been suffering from a case of meatballitis in 2015; his percentage of grooved pitches is actually down/steady for all of his pitches. So this doesn't seem to be related to his increased HR/FB%.

I suppose it's possible that Felix is tipping his hand and giving away his pitches sometimes. Or maybe his pitch mix has occasionally been predictable and hitters are able to sit on a sinker that's out over the plate. But really, this is probably just a case of bad luck over a small sample size. Felix has only allowed 40 fly balls this year. According to FanGraphs, the HR per FB rate doesn't stabilize until 400 fly balls. That's more than two seasons worth of fly balls for the King! Moving forward, a smaller percentage of the balls that are hit in the air will leave the yard. As a result, Felix should give up fewer runs on the long ball; this will likely serve to cancel out some of the negative regression he'll experience in terms of his BABIP and LOB% numbers. In summary, Felix should continue to be Felix... but you already knew that, didn't you?

Go M's.